[Effect of probiotics on Newcastle Disease Virus]

We studied the antiviral activity of probiotics and possible mechanism thereof.

With hemagglutination in vitro and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) of chicken embryo fibroblast (CEF), the hemagglutination titers and virus inhibition rate were respectively determined to evaluate the impact of probiotics on Newcastle Disease Virus (NDV).

Five probiotics and their metabolites could reduce the viral titer of NDV, but the two pathogenic bacteria and their metabolites could not. These results indicated that probiotics may destruct the structure of NDV directly and this effect was strain-specific. Probiotics could inhibit the replication rate of NDV significantly in a dose-dependent manner (P<0.01). The inhibitory rate increased when the cells were pre-treated with probiotics, which indicated that the probiotics might block NDV adsorbing to the cells. The fact that addition of probiotics and NDV at the same time reduced the cytopathic effect (CPE) of cells suggested that probiotics could destruct the viral structure directly; the lower inhibitory rate of viral replication when cells infected with NDV before addition of probiotics to the cells suggested that the probiotics worked hardly after the cells were infected.

Probiotics can not only destruct the virus, but also block the virus infection of the cells and inhibit the viral proliferation in the cells.